The Birth of the Virtual Machine, a Quest for Hybrid CAD

Archimedes, a classical mathematician who died 2,200 years ago, is about to become part of the PLM (product lifecycle management) lexicon.

Soon after the ink dried on its acquisition of UGS, Siemens' Automation & Drives (A&D) division began working on a project dubbed Archimedes. Discussing it in the company's internal publication titled Pictures of the Future, publisher Arthur F. Pease wrote, "Siemens' recent acquisition of UGS has given its [A&D] Group ... the tools to merge the real and virtual worlds of production" ("Factories of the Future — UGS and Siemens," Fall 2007). For more on the Archimedes Project, read "Event Report: [2007] UGS Media/Analyst Conference."

At Siemens' 2008 media and analyst briefing, which took place in Boston, Massachusetts, in May, Michael Weyrich, leader of new-generation business at Siemens A&D, introduced tangible evidence of Archimedes in operation. By marrying UGS's NX to Siemens' motion-control capabilities, Siemens has developed the Virtual Machine, which connects CAM (computer-aided manufacturing) to CNC (computer numerical control).

CNC Behavioral Science
Generally, a CAM program simulates the machining operations by animating the machine's movements based on kinematics, the mechanical motions predicted based on physics. However, in the physical world, the CNC operator uses a controller attached to the machine to perform the required tasks.

"In the Virtual Machine, NX takes into account the unique machine-tool characteristics of the real machine's controller," Weyrich said, "so information like how a machine is configured on a certain shop floor, for example, will be part of the simulation."

With Siemens' Virtual Machine, the simulation process is driven not only by kinematics but also by the motion algorithms used by an actual 840D controller. Therefore, it is expected to faithfully depict the cutting conditions, axis movements, collisions, work piece geometry, and motion behaviors of the machine tools equipped with a Siemens 840D control.

The virtual machine can physically be found at INDEX, a CNC machine supplier headquartered in Esslingen, Germany. It is now part of what the company delivers to its customers along with the physical hardware.

E4DF
Wolfgang Schloegl, Siemens' digital factory team leader, followed Weyrich's virtual machine presentation with another that focused on the virtual factory, or E4DF (engineering for digital factory). In his view, the major shortcomings in today's engineering are:

unsynchronized processes

redundant data entry, processing, and storage

insufficient validation of engineering results

His recommendation? Use Siemens' SIMATIC Automation Designer software along with Teamcenter as the data backbone. In its online literature promoting SIMATIC's openness as an advantage, Siemens states, "The previously separate worlds of mechanical components, electrical systems, and automation are now represented transparently in one plant structure. This guarantees data consistency. The result is that existing software tools can easily be used again and combined with SIMATIC Automation Designer."

With SIMATIC, CAD diagrams form the basis for plant layout. Once read into SIMATIC, they become the touchstones for configuring the production process. "The product has been field-tested for 1.5 years," said Schloegl. "It's now ready in a way that we can sell it."

By the end of this month, SIMATIC 3.0 should be available, along with E-CAD Extension Packages for automatically generating and integrating circuitry design. Schloegl revealed that SIMATIC will begin using JT, a lightweight file format developed by UGS, for visualization of factory components in 2009.

Live Rules Overrule Feature History
Synchronous Technology, Siemens' answer for combining freeform and parametric modeling, had been in incubation in a development lab at UGS before the acquisition. "When Siemens found out we had been working on this, they were delighted," said Chuck Grindstaff, Siemens' executive vice-president of products. With Siemens' contribution to the R&D budget, Synchronous Technology swiftly made its debut last month (for more information, read "Siemens Breaks Free from History."

In the first quarter of 2008, three history-based CAD vendors — Dassault, PTC, and Siemens — unveiled their own solutions that allow CAD users to employ a mix of modeling approaches. In February, PTC introduced a new version of Pro/ENGINEER that incorporates certain freeform-modeling features from CoCreate (acquired by PTC in October 2007). In April, Dassault previewed CATIA Live Shape, a freeform-modeling module for CATIA users.

Evan Yares, a CAD industry veteran in attendance at the Siemens event, said that what CAD vendors are pitching as freeform modeling may be described more accurately as "feature-imprint modeling."

Unlike the freeform-modeling methods found in software programs widely used by animation artists and game developers (such as Autodesk 3d Studio Max or Maya), the method now making its way into CAD packages relies on the recognizable topology of mechanical features (holes, tubes, and shafts) and makes every effort to retain the surface and geometric relationships. Therefore, Yares argued, the deformation is based on the existing imprint of a feature.

Synchronous Technology relies on Live Rules, a set of algorithms for detecting and recognizing standard mechanical features, to let the software intelligently reshape the affected geometry in response to a user's pushes, pulls, and dimension-driven changes. Live Rules can be disabled when a user wants to make an unorthodox change that might break the generally accepted associativities and constraints in a feature. Conversely, users also have the option to place locked constraints (or parameters) on a model.

In the demonstration, Dan Staples, director of Solid Edge product development, demonstrated how one can use Synchronous Technology to edit a Solid Edge assembly containing a SolidWorks part and an Inventor part. The new releases of NX and Solid Edge (dubbed Solid Edge with Synchronous Technology, or SEST for short) both feature Synchronous Technology.

Siemens promotes upcoming releases of NX and Solid Edge with Synchronous Technology as CAD tools with the potential to offer dramatically higher productivity in multi-CAD environments.

Other Highlights
NX 6 features Product Template Studio, a way to publish a simplified parametric model from a complex part as input. The tool is designed to let users automatically generate a brand new part based on an existing one through guided input fields, bypassing the need to directly interact with the geometry.

With NX 6, using the mix-mesh approach, a user can prepare a mesh model for analysis with different mesh densities for different regions. The tool is particularly useful when dealing with products with a mix of simple and complex curvatures or a combination of thick and thin surfaces.

Throughout the last several years, digital prototyping has become the new mantra for CAD and PLM vendors. It's an ambitious vision, wherein everything taking place on the factory floor — from the tilt of an automatic drilling arm to the posture of an assembly worker — is simulated with digital replicas first. Siemens' progress report on the Archimedes Project proves that having a hardware giant for a parent company can be an advantage.

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